**5.5 Organic matter reduction**

There are many industrial applications in which the principal goal of anaerobic digestion is the organic treatment of waste instead of the production of gas. On this subject, the elimination of the difference between the organic matter contained before and after treatment, is a significant parameter that it is necessary to control. This is measured in term of Total solid (TS), volatile solid (VS), total organic carbon (TOC), COD or BOD (Boe & al., 2005). These parameters are appropriate for the control of the anaerobic digestion applied to several types of waste.
